1. Field of the Invention
This invention relates to brake calipers for use with disc brakes.
2. Discussion of Related Art
In typical disc brake assemblies, a rotor is mounted on a wheel hub for rotation. One or more pairs of brake pads, generally designed as friction material carried on a backing plate, are supported on either side of the rotor by a caliper or an anchor bracket. Calipers are designed to apply the braking force by moving a piston relative to the rotor to thereby move the brake pad into and out of contact with the rotor. The pistons are supported in a bore and abut the backing plate of the brake pad to move the brake pad toward the rotor upon application of a braking force. The caliper can be hydraulically actuated, for example, to selectively press the brake pads against the surface of the rotor to stop the rotation of the rotor and hence the wheel hub by forcing hydraulic brake fluid into the piston bore.
The brake pads, which include friction elements, require periodic replacement due to wear. This is especially true in automotive racing where pads may require replacement during a race. In this situation, quick and easy removal is highly desirable.
The prior art has addressed this problem in several different ways. It is known, for example, to replace the entire caliper assembly, including the brake pad. In this case, the brake pads are constrained by a bridge integrally formed with the caliper body, an example of which is shown in FIG. 8A. To replace the brake pad, the caliper assembly must be entirely removed from the vehicle. The advantage of this design is that the bridge provides a maximum degree of stiffness, which enhances braking performance, since it is integrally formed with the caliper body. However, as can be appreciated, removal of the entire caliper assembly requires significant effort. The replacement requires an extended change time.
In another known method of replacement, the bridge is bolted to the caliper body on both sides, as seen in FIG. 8B. The bridge often is formed as an H and two bolts rigidly securing the bridge to the caliper body. Removal and replacement is still complicated as multiple bolts must be removed and reinstalled during replacement, but the change time is less than removing the entire caliper assembly in the integral bridge design.
To decrease change time, one design offers a hinge on one side of the bolted bridge. This type of design is shown in FIG. 8C. That way, a bolt on only one side needs to be removed to swing the bridge and allow for pad replacement. This design offers comparable stiffness to the fully bolted bridge design and allows slightly faster change time.
To alleviate the bolting issue, some race caliper manufacturers have replaced the bridge with a spring clamp for quick pad changes, as illustrated in FIG. 8D. The spring clamp holds the pads in vertically, similar to the integral and bolted bridges, but does not offer the stiffness of the integral and bolted bridges. It has also been know to offer combined spring clamp and bolted bridge design so that the design can be chosen based on the particular event and pad change requirements, as shown in FIG. 8E.
Thus, there is a need for a caliper that allows quick pad removal while offering a high degree of caliper stiffness.